1. Technical Field
The present invention relates to slot antennas and, more particularly, relates to a compact configuration for a plurality of slot antenna elements.
2. Description of the Related Art
Because they can be made conformal to metallic surfaces, arrays of slot antennas have been used in aeronautical applications. The antenna elements in these prior aeronautical applications have been spaced relatively far apart to avoid coupling between the antenna elements.
A compact slot antenna is desired with low coupling between the antenna elements. Further, a slot antenna having separately connected antenna elements for different functions is desired.
A slot antenna has electrically independent antenna elements in close proximity with low mutual coupling therebetween. A multilayer dielectric substrate has a conductive layer. A pair of coplanar elongated slots is formed in the conductive layer and configured in a substantially collinear fashion with one another. A pair of transmission lines of conductive traces is formed on the multilayer dielectric substrate coupled to a respective slot. Preferably the pair of slots is notches configured in directions opposing one another. In a further aspect of the invention an additional slot is formed in the conductive layer between the pair of the slots and an additional transmission line of a conductive trace is formed on the multilayer dielectric substrate and coupled thereto. Preferably the another slot is orthogonally configured relative to the pair of the slots to provide for polarization diversity with minimal coupling.
Associated application circuitry can be disposed on the same dielectric substrate as the antenna element. Depending on the antenna application desired, receive and transmit amplifiers can be directly coupled to the antenna transmissions lines, thus avoiding the need for a duplexer or transmit/receive switch component. For diversity applications that use a single receiver, a diversity switch can be used to select between two of the antenna elements, preferably to the orthogonal antennas for polarization diversity.
The details of the preferred embodiments of the invention may be readily understood from the following detailed description when read in conjunction with the accompanying drawings wherein: